wet fouled plugs

[foulpole18]

I have a 89 25hp Johnson outboard that keeps wet fouling plugs. I ave checked the gap on the plugs and they are correct. The book says it could be a fuel pump issue.

I'm thinking if I replace the screen and diaphragm it should fix the problem.

Do you think I'm on the right path?

Thanks in advance

Brian

[boatfixer]

Is it happening to both plugs? If yes, then I don't suspect the fuel pump because it gets it's pulse from only 1 cylinder.

Are you positive it's gas and not water?

[foulpole18]

It smells and looks like gas/oil. If it's gas/oil, what could be causing it?

[Surface Tension]

When is it fouling the plugs?

Runs fine but sometime during the outing the plugs foul?

Or right off the bat?

Your remote tank can build up pressure when not in use.

If the outboard is trailerd and stored tilted up, the float in the carb drops and will let that gas flow through.

Eliminate this possibility by removing the fuel line to the outboard at the end of your outing when pulling up to the dock. Let outboard run till the fuel in carb is run dry.

Next time out, with boat in the water and outboard tilted down. Vent the fuel tank, hook up the fuel line, prime using the bulb. After the proper fuel level is reached from priming the bulb should be hard. Let us know if you have fouling.

If you can continue to prime the bulb and are certain your pushing fuel each time you prime then the inlet valve inside the carb isn't seating. The inlet valve and float work together. Could be improper float drop or debris in the inlet valve or worn inlet valve.

[jentz]

What are you gapping the plugs at? If I'm not mistaken around that time the plug gaps went from .30 to .40

[Minnesota Fats]

Spark plug heat range too cold?

[foulpole18]

It fouls the plugs right away. I just replaced the plugs and I did no trolling and very little idleing and the plugs have a wet spot. It is not the whole plug but about a quarter of it. Both plugs have the same oil? mark on them.

The plugs are gapped to .40 like the service manual says and it is the listed plug per the manual also.

The motor is always down so I don't think that could be causing the problem.

This is a little annoying. Its hard to trust it when sometimes its a pain to get running.

[eurolarva]

If you are not comfortable doing a link and sync I would take it in and have it done. Your carbs could be running too rich and this could be because the rubber has hardened with the invent of ethanol. I am guessing you will need carb kits and probably a new diaphram. On a two stroke you want your plugs slightly wet. Better to run too rich then too lean. Running the carbs dry is not a good practice. When running them dry they tend to over rev when the only remaining gas is vapor and without the oil in the gas to lube the pistons you run a chance of scoring or even damaging your engine.

[Surface Tension]

I'm not understanding this.

"It is not the whole plug but about a quarter of it"

Given the information you've provided, the steps I posted are procedures to diagnose your problem. What we're trying to do is eliminate what it could be and find what it is. That information wasn't a stab in the dark, so do as I asked and post results or we won't get anywhere.

Another step in this process would be to take a sample of fuel from the bottom of your gas tank. I say bottom because if you have water in the tank it'll settle to the lowest point in the tank. Do this after the boat has been at rest and syphone or pump that into a clear glass jar.

Another question is what type of fuel have you been using. Oxy or nonoxy gas. If you've used oxy then the water will be mixed into the fuel and will look like swirls in your test sample.

Non oxy fuel will have the water at the lowest point.

I mention this because you said the whole plug isn't fouled. Which could be moisture on the plug. This water will separate from the fuel once its gone through the combustion process. What isn't turned into steam and out your exhaust will condense.

[foulpole18]

I'm not understanding this.

"It is not the whole plug but about a quarter of it"

Given the information you've provided, the steps I posted are procedures to diagnose your problem. What we're trying to do is eliminate what it could be and find what it is. That information wasn't a stab in the dark, so do as I asked and post results or we won't get anywhere.

Another step in this process would be to take a sample of fuel from the bottom of your gas tank. I say bottom because if you have water in the tank it'll settle to the lowest point in the tank. Do this after the boat has been at rest and syphone or pump that into a clear

Another question is what type of fuel have you been using. Oxy or nonoxy gas. If you've used oxy then the water will be mixed into the fuel and will look like swirls in your test sample.

Non oxy fuel will have the water at the lowest point.

I mention this because you said the whole plug isn't fouled. Which could be moisture on the plug. This water will separate from the fuel once its gone through the combustion process. What isn't turned into steam and out your exhaust will condense.

The motor is never stored or trailered in a raised position. The gas is non oxy and doesn't appear to have water in it.

The motor starts and runs ok but the longer it runs it starts to run rough. If it sits for awhile it will be hard to start (kind of a pain when long way from launch).

When looking at the plugs I just put in, it had a spot which was about a 1/4 of the face of the plug. Other plugs that have been in longer will have a larger area coated in what appears to be oil/gas?

Thanks for the help, I'm trying to work on it between work and kids.

Brian

[Drail1313]

foulpole18,

DO NOT WASTE YOUR TIME!!! I to had a older 25hp Johnson that did the same thing and a put WAY to much time and money into different fixes that did not seem to fix it and it was easier to just have a change of cheap plugs handy.

my2cents